1. Field of Invention
This invention relates to a blanket for covering at least a portion of the body of a human, or other animal, in order to bath the body portion in a conditioned gas. More specifically, the present invention is related to an inflatable thermal blanket having air flow channels for directing a conditioned gas, such as, for example, heated air, to a selected portion of the body of a user while allowing a medical person to access a portion of the body with sterile access.
2. Description of the Related Art
Inflatable thermal blankets which are used to communicate a conditioned gas, such as heated or cooled air, to a patient are known in the art. Such thermal blankets typically have an inflatable portion provided with an inlet port for placing the inflatable portion in fluid communication with a source of pressurized, conditioned gas such that the inflatable portion can be selectively inflated. The inflatable portion generally has an inner surface which is gas pervious, or which is otherwise adapted to communicate the conditioned gas used to inflate the blanket to the user. Such thermal blankets are often used to treat conditions such as hypothermia, or used to reduce the body temperature of a user in circumstances where the body temperature is inappropriately high. For example, where a patient is being treated for hypothermia, at least a portion of the patient's body is covered with the thermal blanket, and warm air is pumped into the inflatable portion. The warm air used to inflate the inflatable portion is thereafter communicated through the inner surface of the inflatable portion so as to bath the body portion covered by the blanket in warm air. Examples of such thermal blankets are disclosed in U.S. Pat. Nos. 5,184,612; 5,304,213; and 5,324,320.
Whereas prior art thermal blankets serve to deliver conditioned air to a patient, the temperature of the air being communicated through the inner surface of the inflatable portion, and the surface temperature of the inner surface, can vary greatly over the area of the inner surface. For example, if heated air is pumped into the inflatable portion through the inlet port, the air within the blanket near the inlet port tends to be substantially higher in temperature than the air within the blanket which is remote from the inlet port. Accordingly, the inner surface of the blanket proximate the inlet port, and the air communicated to the patient through the inner surface of the blanket proximate the inlet port, can be uncomfortably, or damagingly, hot when the blanket is otherwise communicating air of the desired temperature to the patient. Whereas the temperature of the air entering the inlet port can be reduced to avoid uncomfortable, or damaging, hot spots near the inlet port, such a reduction of temperature can compromise the overall effectiveness of the thermal blanket.
U.S. Pat. No. 5,443,488, titled “Thermal Blanket with Surgical Access,” issued to Namenye, et al., on Aug. 22, 1995, discloses “a disposable pneumatic thermal blanket for controlling a patient's body temperature wherein the blanket includes structure for providing access through the blanket for surgical purposes.” The '488 patent discloses an access opening 74 through the blanket 10 formed by a plurality of perforated slits 26, 28, 30, 34, 38 extending through the blanket 10. The perforations initially hold the shape of the blanket 10 during shipping and handling and weaken the blanket 10 so that the desired access opening 74 is formed by pulling the blanket 10 apart upon opposite sides of the slits 26, 28, 30, 34, 38. The excess blanket material or flaps 68 are rolled to form rolls 72, which expose a portion of the body under the blanket 10.
U.S. Pat. No. 5,674,269, titled “Patient Warming System with User-Configurable Access Panel,” issued to Augustine on Oct. 7, 1997, discloses a U-shaped pneumatic thermal device 100 for controlling a patient's body temperature and a deformally resilient, insulating access panel 118 between the tube legs 110, 112 of the thermal device 100. The access panel 118 has pliable, opposing fingers 200, 201, which are pulled away from the patient 104 to provide access. The panel 118 has pliable, opposing fingers 206, 207, which are tucked between the patient 104 and the device 100 to provide access. The fingers 200 to 207 are created by tearing perforations between the fingers to be separated from the panel 118.